I think he's talking thematically rather than literally in like the Injustice sense that it would collapse into fascist terror if she weren't there. She's a character that can, when used properly, maneuver through the entire DCU and serve a connection between various elements of the universe and through her work get to important truths that other characters wouldn't necessarily have access to. You can drop her into any corner of the DCU and have her fit a story through her role as a POV character.